Ascochyta

Ascochyta is a genus of ascomycete fungi in the family Didymellaceae, order Pleosporales. Members of this genus are plant pathogens that cause diseases commonly referred to as ascochyta blight or leaf spot on a range of hosts, especially legumes. The genus comprises numerous species described from different plants, and taxonomic work frequently relies on morphological features complemented by molecular data.

The most economically important diseases are ascochyta blights of chickpeas (Ascochyta rabiei), faba beans (Ascochyta fabae), peas (Ascochyta pisi), and lentils (Ascochyta lentis). Symptoms typically begin as small dark lesions on leaves and stems that expand into necrotic blotches. Infected plants may show premature defoliation, reduced vigor, and lower yields. Pods and seeds can also be affected, diminishing market value and storage quality.

Biology and epidemiology: Ascochyta species reproduce asexually by conidia produced in pycnidia and sexually by ascospores in pseudothecia. Spores are disseminated by wind and rain-splash, with infection favored by cool, wet conditions during vegetative growth. Inoculum can persist in crop debris and may be seedborne, contributing to primary infections in new growing seasons.

Management typically requires an integrated approach. Practices include using resistant or tolerant cultivars where available, crop rotation and field sanitation, destruction of infested residue, and the use of certified, disease-free seed. Fungicide applications may be employed in high-risk areas, particularly when environmental conditions favor disease development.

Distribution is global in temperate regions, with outbreaks linked to favorable weather and agricultural practices. Accurate species identification assists in selecting appropriate management strategies.